Fuel tanks, particularly in automobiles, typically contain a fuel pump which may be mounted on the bottom of the tank. It is desirable to position the inlet of the fuel pump as near as possible to the lowest level in the tank so that a source of fuel will be available even when fuel level is low. Despite such a placement of the fuel inlet, events during vehicle operation such as cornering, braking and acceleration can cause the fuel to "slosh" around, potentially uncovering the fuel pump inlet. Driving or parking on a slope could similarly result in the fuel pump inlet being uncovered. When the inlet is exposed, the fuel pump sucks air (or fuel vapor) causing the engine to stammer and stall. An additional problem occurs at engine start-up when fuel tank level is low and there is insufficient fuel at the pump inlet.
Various methods have been devised to solve the above mentioned problems. Damming means which form a reservoir within a cylinder in the tank to keep fuel covering the fuel pump inlet was disclosed in U.S. Pat. Nos. 4,397,333 and 4,503,885. Those patents also disclosed a jet aspirator to continually draw fuel into the reservoir. The reservoirs in these devices are relatively small and the jet aspirator does not keep the cylinder filled after the engine is turned off since fuel leaks out through the fuel return conduit. Thus, the level of fluid available at engine start-up is limited to that in the reservoir.
Another method for providing fuel to the fuel pump intake is to induce fuel into a reservoir by directing return fuel over a ramp past an opening in the reservoir. Several patents disclose variations on this method, including U.S. Pat. No. 4,899,784. However, fuel will leak out of the swirl pot of this device when vehicle operation ceases.